Improvement in hoisting-machines



tait-:nl fettine @sind demise.

WILLIAM M; SMITH, or AU-GUsTA,`eEoRGIA.

Letters Patent No. 93,490, dated August 10, 1869.

nvrPRovnr/IENT IN HoIsTING-MAGHINES.

The Schedule vreferred to in these Letters Patent and making partei' the same.

' `Figures l and 2 represent a front and end view of al combination of pulley-blocks and endless ropes, to which my limprovements have been applied.

Figure 3 represents .a section of the lower pulleyblocks G and D in figs.` 1 and 2.

Figures`4 and 5 represent, also, sections of figs. l and 2, showing the spring-clamps in the periphery of the differential pulley-blocks;

Similar letters of reference, where they occur in the separate figures, denote like parts in al1 the drawings,

All combinations of pulleyblocks and ropes now known or used-for the purpose of elevating weights, require a constant and vigorous holding yon to that end oi' the rope paid off from the revolvingblock which elevates the object being raised, to prevent the same from receding. In this'particular-rny improvement diers from all other-s',v and does notrequire the holding or fastening of anyrop'e. to .prevent the objectbeing-,elevatedfrom receding,l but-willrgidly'hold `the Vsame to the point attained in its elevation, whenever and as often as the revolving elevating-blocks shall be stopped.

In addition to this rnateiial feature of said improvey ment, I have also constructed, in combination with an endless cord, two small adjustable pulley-blocks, with `one or two cranks, as may be desired, rigidly affixed to the shaft of the lesser one, for the purpose of drivingthe elevating-blocks when very heavy objects are to be lifted, whereby kthe power of one man 'is multiplied 'centimes when said cranks are but fourteen inches in length. o l

Having thus recited-some of the beneficial results to be attained in the use of' this' improvement, I will now proceed to describe the same with reference to the drawings, that others skilled in the art may be enbled to manuihctm'e and use my invention.

A B represent two pulley-blocks, of different diameters, with spur-wheels firmly aiiixed on the outer ends 0i' each, and rigidly fastened together on the same horizontal shaft, the ends of which rest inthe iron support o r hanger E, suspended byhook F to crossbeam G.

The periphery of the pulley-block'A must have a groove in the same, fully equal in width and depth to thediarneter ofthe endless rope desired to be used in combination therewith, and a suiiicient number of spring-clamps, properly spaced and inserted therein,

to prevent the endless cord from slipping around the"- samewhen propelled by driving-pulley H;

Pulley-block A can be madev of wood orA iron. It' made of iron, four or six places, accordingA to the diameter of the same, must be properly shaped and ymoulded in the periphery thereof, for the insertion of v said spring-clamps.' If made of wood, their places. can

easily bev cut withfhand-s'aw and chisel.

. Pullcyeblock-B is very diiierently constructed from l A, and can be made of wood, iron, -or India rubber. The latter material is far preferable, and when used for that purpose should have on. either side two iron-supports, made in the usual shape of thin cast' iron washers, graduating in thickness from the centre to a thin edge, and having a diameter nearly equal to that'of therubber pulley B, required to be thus sup` ported. A y

The periphery of pulley B can be made either plain, irregular, orV grooved, butv innst not be wider on its face-than the. diameter o theendless rope to beplaeed and operated in the grooved peripheries o' pulleys :A and C.,

Pulley-blocks C D are made' 'in every respect the same as A B,- G' like A, and D like B, except that C revolves on its shaft, while D is rigidly fastened thereto,

`reckoning from the base of the grooved periphen'es of each, that will bring the outer surface of the endless cord to be placed and operated therein exactly upon a horizontal planewith the pitch-line of their respective spur-wheels.

The pulleys B and D should exceed one thirty-second of an inch in diameter that of their respective spur-wheels, reckoning from the pitch-lines of the same.

The pulley-blocks C D are placed directly underneath and geared with the blocks A BgDfunder A, and G under B, and are supported in that relative position byV shaft I, resting in the adjustable bearings J J, which are snugly fitted in the slotted ends of hanger E.

Such an adjustment of the upper and nether diiferential pulley-blocks, as above set forth, is absolutely necessary, that each may have the same uniform ac 

